Highpass sallen-key switched capacitor question

Started by Eddododo, July 28, 2014, 11:32:42 PM

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Eddododo

I have a simple highpass, with a switch that switches 'in' a second set of caps to run parallel to the original caps, lowering the frequency.
easy enough, but it, probably obviously, pops BADLY

could I use a high value resistor to ground switched in series with the aux caps when 'out' of the circuit ( a)
or use permanent high value resistors in parallel to the caps to ground (  b )


Eddododo

i have buffers and resistor values etc etc of course, just being lazy and demonstrative

R.G.

Put a high value (1M or so) resistor in series with the second caps. Use your switch to "short out" the resistor. That way the caps are always pulled to the same DC level, and you should not get pops.
R.G.

In response to the questions in the forum - PCB Layout for Musical Effects is available from The Book Patch. Search "PCB Layout" and it ought to appear.

PRR

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Eddododo

! Excellent

always seems so obvious, afterwards.

Thanks!